President Barack Obama spoke with Cuban President Raul Castro Tuesday in a phone call that lasted about an hour and reflected the first communication at the presidential level with Cuba since the Cuban revolution, according to White House officials. Obama announced Gross' release and the new diplomatic stance at noon in Washington. At around the same time, Cuban president Raul Castro was set to speak in Havana.

President Obama announced a major loosening of travel and economic restrictions on the country. And the two nations are set to re-open embassies, with preliminary discussions on that next step in normalizing diplomatic relations beginning in the coming weeks, a senior administration official tells CNN.

Talks between the U.S. and Cuba have been ongoing since June of 2013 and were facilitated by the Canadians and the Vatican in brokering the deal. Pope Francis -- the first pope from Latin America -- encouraged Obama in a letter and in their meeting this year to renew talks with Cuba on pursuing a closer relationship.

Gross' "humanitarian" release by Cuba was accompanied by a separate spy swap, the officials said. Cuba also freed a U.S. intelligence source who has been jailed in Cuba for more than 20 years, although authorities did not identify that person for security reasons. The U.S. released three Cuban intelligence agents convicted of espionage in 2001.

The developments constitute what officials called the most sweeping change in U.S. policy toward Cuba since 1961, when the embassy closed and the embargo was imposed.

Officials described the planned actions as the most forceful changes the president could make without legislation passing through Congress.

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For a President who took office promising to engage Cuba, the move could help shape Obama's foreign policy legacy.

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Kim Dong Chul, a South Korean-born American citizen detained in North Korea, is escorted to his trial April 29 in Pyongyang. A North Korean court sentenced Kim to 10 years in prison for what it called acts of subversion and espionage. North Korea watchers interpret the detainment of Americans and other foreign citizens as a collection of bargaining chips by the reclusive regime.

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University of Virginia student Otto Frederick Warmbier was detained by North Korea after being accused of carrying out "a hostile act" against the government, state media reported. In March, he was sentenced to 15 years of hard labor for allegedly removing a political banner from a Pyongyang hotel.

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Jason Rezaian, The Washington Post's bureau chief in Tehran, was released January 16 as part of a prisoner swap. Rezaian was convicted by an Iranian Revolutionary Court in October, according to Iran's state-run media. Rezaian was reportedly facing up to 20 years, but the sentence was not specified. The journalist was taken into custody in July 2014 and later charged with espionage; the Post has denied all allegations against him. His wife, Yeganeh Salehi, also was detained in July 2014 but later released.

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Saeed Abedini, a U.S. citizen of Iranian birth, was freed as part of a prisoner swap that included Washington Post journalist Jason Rezaian on January 16. Abedini was sentenced to eight years in prison in January 2013. He was accused of attempting to undermine the Iranian government and endangering national security by establishing home churches. He was detained in Iran on September 26, 2012, according to the American Center for Law and Justice.

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Amir Hekmati, a former U.S. Marine charged with spying, was freed as part of a prisoner swap that included Washington Post journalist Jason Rezaian on January 16. An Iranian court threw out a 2011 death sentence forHekmati, but he was secretly retried in Iran and convicted of "practical collaboration with the U.S. government," his sister told CNN on April 11. He was sentenced to 10 years in prison, she said. Hekmati was detained in August 2011 during a visit to see his grandmother. His family and the Obama administration deny accusations he was spying for the CIA.

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Siamak Namazi, a Dubai-based businessman with dual U.S. and Iranian citizenship, was detained while visiting relatives in Tehran, the Wall Street Journal reported October 29, citing unnamed sources. The Washington Post also reported his detention, citing a family friend who spoke on condition of anonymity. The Post reported that it wasn't clear what Namazi is alleged to have done. His detention would bring to five the number of Americans detained or unaccounted for in the Islamic republic.

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Scott Darden was taken hostage by Houthi rebels in Yemen in March 2015. He was captured while working for New Orleans-based Transoceanic Development, according to a source close to his family.

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Retired FBI agent Robert Levinson has been missing since 2007. His family says he was working as a private investigator in Iran when he disappeared, and multiple reports suggest Levinson may have been working for the CIA. His family told CNN that they have long known that Levinson worked for the CIA, and they said it's time for the government to lay out the facts about Levinson's case. U.S. officials have consistently denied publicly that Levinson was working for the government, but they have repeatedly insisted that finding him and bringing him home is a "top" priority. The FBI increased its reward for information on Levinson from $1 million to $5 million.

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Mothers Linda Boyle, left, and Lyn Coleman hold photo of their married children, Joshua Boyle and Caitlin Coleman, who were kidnapped by the Taliban in late 2012. Coleman was pregnant when she was kidnapped and is believed to have had a child in captivity.

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Jailed since 2013 and sentenced to life for supporting the Muslim Brotherhood in Egypt, Mohamed Soltan was eventually released, the U.S. Embassy in Cairo said in May 2015. Soltan's family denies he belonged to the Brotherhood. Soltan had been a dual U.S. and Egyptian citizen, but he renounced his Egyptian citizenship as a condition of his release.

One of three Americans detained in North Korea, Jeffrey Edward Fowle was released and sent home, a State Department official told CNN in October 2014. Fowle was accused of leaving a Bible in a hotel where he was staying. North Korea announced Fowle's detention in June of that year, saying he had violated the law by acting "contrary to the purpose of tourism." Fowle told CNN: "I've admitted my guilt to the government and signed a statement to that effect and requested forgiveness from the people and the government of the DPRK."

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In May 2013, a North Korean court sentenced Kenneth Bae, a U.S. citizen, to 15 years of hard labor for committing "hostile acts" against the state. North Korea claimed Bae was part of a Christian plot to overthrow the regime. In a short interview with CNN in September 2014, Bae said he is working eight hours a day, six days a week at a labor camp. "Right now what I can say to my friends and family is, continue to pray for me," he said. After months in detention, he and fellow American detainee Matthew Todd Miller were released in November.

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Miller, an American sentenced to six years of hard labor in North Korea, was one of three Americans who spoke to CNN's Will Ripley in September 2014 and implored the U.S. government for help. The 24-year-old was accused of tearing up his tourist visa and seeking asylum upon entry to North Korea.

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American journalist Peter Theo Curtis was handed over to U.N. peacekeepers in August 2014 after nearly two years in captivity. He is believed to have been captured in October 2012 and held by the al-Nusra Front, a Syrian rebel group with ties to al Qaeda.

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Alan Gross, at right with Rabbi Arthur Schneier, was jailed while working as a subcontractor in Cuba in December 2009. Cuban authorities say Gross tried to set up illegal Internet connections on the island. Gross says he was just trying to help connect the Jewish community to the Internet. Former President Jimmy Carter and New Mexico Gov. Bill Richardson both traveled to Cuba on Gross' behalf. He was eventually released in December.

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This undated image provided by the U.S. Army shows Sgt. Bowe Bergdahl, who had been held by insurgents in Afghanistan since 2009. The White House announced Bergdahl's release on May 31, 2014. Bergdahl was released in exchange for five senior Taliban members held by the U.S. military. In March 2015, the U.S. military charged Bergdahl with one count each of "Desertion with Intent to Shirk Important or Hazardous Duty," and "Misbehavior Before The Enemy by Endangering the Safety of a Command, Unit or Place."

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U.S. tourist and Korean War veteran Merrill Newman arrives at the Beijing airport on December 7, 2013, after being released by North Korea. Newman was detained in October 2013 by North Korean authorities just minutes before he was to depart the country after visiting through an organized tour. His son Jeff Newman said the Palo Alto, California, man had all the proper paperwork and set up his trip through a North Korean-approved travel agency.

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Y – Mexican authorities arrested Yanira Maldonado, a U.S. citizen, right, in May 2013, for alleged drug possession. She and her husband, Gary, were traveling from Mexico back to the United States when their bus was stopped and searched. She was released a few days later and is now back in the United States.

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North Korea has arrested Americans before, only to release them after a visit by a prominent dignitary. Journalists Laura Ling, center, and Euna Lee, to her left, spent 140 days in captivity after being charged with illegal entry to conduct a smear campaign. They were freed in 2009 after a trip by former President Bill Clinton.

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Former President Jimmy Carter negotiated the release of Aijalon Gomes, who was detained in 2010 after crossing into North Korea illegally from China. Analysts say high-level visits give Pyongyang a propaganda boost and a way to save face when it releases a prisoner.

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Detained in April 2011, Eddie Yong Su Junwas released by North Korea a month afterward. His alleged crime was not provided to the media. The American delegation that secured his freedom included Robert King, the U.S. special envoy for North Korean human rights issues.

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Without any apparent U.S. intervention, Robert Park was released by North Korea in 2010. The Christian missionary crossed into North Korea from China, carrying a letter asking Kim Jong Il to free political prisoners and resign. North Korea's state-run news agency said Park was released after an "admission and sincere repentance of his wrongdoings." Here, Park holds a photo of Kim and a malnourished child during a protest in Seoul.

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Josh Fattal, center; Sarah Shourd, left; and Shane Bauer were detained by Iran while hiking near the Iraq-Iran border in July 2009. Iran charged them with illegal entry and espionage. Shourd was released on bail for medical reasons in September 2010; she never returned to face her charges. Bauer and Fattal were convicted in August 2011, but the next month they were released on bail and had their sentences commuted.

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Haleh Esfandiari, an Iranian-American scholar, was detained at Iran's Evin Prison, spending months in solitary confinement before Iran released her on bail in August 2007. Esfandiari was visiting her ailing mother in Tehran when she was arrested and charged with harming Iran's national security.

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Sixteen Americans were among the dozens arrested in December 2011 when Egypt raided the offices of 10 nongovernmental organizations that it said received illegal foreign financing and were operating without a public license. Many of the employees posted bail and left the country after a travel ban was lifted a few months later. Robert Becker, right, chose to stay and stand trial. He spent two years in prison and has since returned to the United States.

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Filmmaker Timothy Tracy was arrested in Venezuela in April 2013 on allegations of funding opponents of newly elected President Nicolas Maduro, successor to the late Hugo Chavez. Tracy went to Venezuela to make a documentary about the political division gripping the country. He was released in June 2013.

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"We are charting a new course toward Cuba," a senior administration official said. "The President understood the time was right to attempt a new approach, both because of the beginnings of changes in Cuba and because of the impediment this was causing for our regional policy."

Gross was arrested after traveling under a program under the U.S. Agency for International Development to deliver satellite phones and other communications equipment to the island's small Jewish population.

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Cuban officials charged he was trying to foment a "Cuban Spring." In 2011, he was convicted and sentenced to 15 years in prison for attempting to set up an Internet network for Cuban dissidents "to promote destabilizing activities and subvert constitutional order."

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Senior administration officials and Cuba observers have said recent reforms on the island and changing attitudes in the United States have created an opening for improved relations. U.S. and Cuban officials say Washington and Havana in recent months have increased official technical-level contacts on a variety of issues.

Gross' lawyer, Scott Gilbert, told CNN last month the years of confinement have taken their toll on his client. Gross has lost more than 100 pounds and is losing his teeth. His hips are so weak that he can barely walk and he has lost vision in one eye. He has also undertaken hunger strikes and threatened to take his own life.

With Gross' health in decline, a bipartisan group of 66 senators wrote Obama a letter in November 2013 urging him to "act expeditiously to take whatever steps are in the national interest to obtain [Gross's] release."

The three Cubans released as a part of the deal belonged the so-called Cuban Five, a quintet of Cuban intelligence officers convicted in 2001 for espionage. They were part of what was called the Wasp Network, which collected intelligence on prominent Cuban-American exile leaders and U.S. military bases.

The leader of the five, Gerardo Hernandez, was linked to the February 1996 downing of the two civilian planes operated by the U.S.-based dissident group Brothers to the Rescue, in which four men died. He is serving a two life sentences. Luis Medina, also known as Ramon Labanino; and Antonio Guerrero have just a few years left on their sentences.

The remaining two -- Rene Gonzalez and Fernando Gonzalez -- were released after serving most of their 15-year sentences and have already returned to Cuba, where they were hailed as heroes.

Wednesday's announcement that the U.S. will move toward restoring diplomatic ties with Cuba will also make it easier for Americans to travel to Cuba and do business with the Cuban people by extending general licenses, officials said. While the more liberal travel restrictions won't allow for tourism, they will permit greater American travel to the island.

Secretary of State John Kerry has also been instructed to review Cuba's place on the State Sponsors of Terrorism list, potentially paving the the way a lift on certain economic and political sanctions.

The revised relationship between the U.S. and Cuba comes ahead of the March 2015 Summit of the Americas, where the island country is set to participate for the first time. In the past, Washington has vetoed Havana's participation on the grounds it is not a democracy. This year, several countries have said they would not participate if Cuba was once again barred.

While only Congress can formally overturn the five decades-long embargo, the White House has some authorities to liberalize trade and travel to the island.

The 1996 Helms-Burton Act, which enshrined the embargo into legislation, allows for the President to extend general or specific licenses through a presidential determination, which could be justified as providing support for the Cuban people or democratic change in Cuba. Both Presidents Clinton and Obama exercised such authority to ease certain provisions of the regulations implementing the Cuba sanctions program.

In an effort to boost the nascent Cuban private sector, the President will also allow expanded commercial sales and exports of goods and services to Cuba, particularly building materials for entrepreneurs and private residences, and allow greater business training, as well as permit greater communications hardware and services to go to the island.

Other announced changes permit U.S. and Cuban banks to build relationships and travelers to use credit and debit cards. U.S. travelers will be allowed to import up to $400 worth of goods from Cuba, including $100 in alcohol and tobacco -- even Cuban cigars. Remittances by Americans to their families back in Cuba will also be increased to approximately $2,000 per quarter.

Officials stressed the moves were not being undertaken to prop up the Castro regime, but rather to encourage further reforms on the island.

"None of this is seen as a reward. All of this is seen as a way of promoting change in Cuba because everything we have done in the past has demonstrably failed," another senior administration official said. "This is not the U.S. government saying Cuba has gotten so much better. It is still an authoritarian state and we still have profound differences with this government."

"But if we hope for change with Cuba, we must try for a different approach. And we believe that considerably more engagement with the Cuban people and the Cuban government is the way to do that," the official said, adding that the United States "will not for a moment lessen our support for improvement in human rights."

To that end, Cuba has agreed to release 53 political prisoners from a list of names provided by the United States. At least one of the prisoners has already been released. Havana has also agreed to permit significant access by its citizens to the Internet and allow the International Committee of the Red Cross and United Nations human rights officials back on the island for the first time in years.

Talks on a deal began between senior White House and Cuban officials last year and happened in fits and starts, officials said. The officials praised the role the Vatican played as guarantor of the process.

Officials would not reveal the name of the U.S. intelligence source, but officials said he was the individual who revealed to the U.S. the Wasp network, which included the Cuban Five.

"He was a very important hero," the U.S. official said.

The moves are far more sweeping than the last action Obama took toward Cuba in January 2011, when he eased restrictions on travel to and from the island. Relations have been largely frozen since Gross' conviction and the White House has made his release a condition of improved ties.

In 2013, Obama drew praise from advocates of changing U.S. policy toward Cuba when he said the U.S. had to be "creative" and "thoughtful" about fostering change on the island.

"The notion that the same policies that we put in place in 1961 would somehow still be as effective as they are today, in the age of the Internet and Google and world travel, doesn't make sense," Obama said at a November 2013 fundraiser in Florida. "We have to continue to update our policies."